Movement Ecology of Early Juvenile Round Goby
Bibliographic record
Abstract
Movement plays a critical role in shaping survival, dispersal, and population dynamics of aquatic species. For invasive species, movement traits can determine both the likelihood of establishment and the pace of range expansion. The round goby (Neogobius melanostomus), one of the most successful aquatic invaders in the Great Lakes and European waters, has spread rapidly since its introduction in the early 1990s. Yet, despite increasing research attention, the traits that influence dispersal in its early life stages remain poorly understood. Here, I investigated how ontogeny, diel activity, and environmental cues influence movement, feeding ecology, and dispersal potential of early juvenile round goby (<25 mm SL). First, I quantified swimming capacity and swimming behaviour in very small juveniles, showing that despite their small body size, early juveniles exhibit considerable swimming capacity that may facilitate dispersal. Second, I examined diel vertical migration (DVM) in laboratory and field settings, providing the first evidence of round goby DVM in Lake Ontario. Early juveniles were observed at the water surface but only at night and similarly showed more vertical movement upwards in the dark in laboratory experiments. This upwards swimming behaviour likely increases their exposure to currents and human-mediated transport vectors, suggesting a mechanism for long-distance dispersal. Third, I characterized ontogenetic shifts in habitat use, diet, and morphology. Smaller juveniles found at the surface consumed mainly zooplankton, including pelagic taxa. In contrast, larger juveniles found on the substrate were primarily fed on a combination of zooplankton and benthic macroinvertebrates. Morphological changes, such as downward orientation of the mouth and eye positioning rotating dorsally, mirrored this pelagic-to-benthic transition. Together, the results of this thesis show that early juvenile round goby display complex movement and behavioural traits that may facilitate dispersal and survival. These findings provide a mechanistic framework for understanding how early life stages can contribute to population establishment and range expansion.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".